What is the ruling on selling a piece of land endowed for building a mosque, which its owner donated but is unable to build upon, due to its small size and the refusal of donors to build on it, and contributing its price to building another mosque, or donating its price to the poor and needy?

If it is difficult to build a mosque on a specific plot of land, it is permissible to sell it and purchase another plot for building a mosque, or to contribute its price towards that. It is not permissible to donate its price to the poor and needy or to any other charitable work. Rather, it must be used for building a mosque, in order to preserve the meaning and purpose of the endowment (waqf).